Depending on the properties of the ocean floor on which the offshore oil drilling or production platforms are situated, the steel anchoring pipes of these platforms are inserted, for example, into the ocean floor by being rammed into place and held there entirely due to friction in the seabed. If this is not enough, an alternative is to introduce underwater concrete or the like into the base of the anchoring pipes thereby created, in which case some of the concrete may escape from the lower end of the pipe into the surrounding ocean floor and form an artificially created foundation anchored in the ocean floor after it hardens, thereby adding the anchoring effect to the effect of the weight of the concrete filling the lower portion of the respective pipe up to a certain height. Regulations that apply to the dismantling of platforms often require the anchoring pipes to be cut off a certain distance below the ocean floor.
Methods and devices for separating upright pipes of a greater length and greater diameter anchored in the ground at their lower ends have previously been described. DE 196 20 756 A1 describes such a method and such a device. A disadvantage of previously-described methods and devices is that they sometimes do not function as reliably as desired under extremely rough ambient conditions (sea water often under high pressure, mixed with drilled-out concrete or the ocean floor) and/or a great effort is required to support and/or secure the pipe that is separated.